## Chemistry: The Central Science (13th Edition)

Just remember that: - Energy must be absorbed to move an electron from a lower state (lower energy) to a higher state (higher energy). - Energy would be emitted as an electron moves from a higher state (higher energy) to a lower state (lower energy). The addition of the electron to an atom is an interesting case. In this case, since the electron is added from outside, we assume its initial position is in the n = $\infty$ state. Afterwards, it ends up in the n = 3 state. Therefore, a movement from higher state (n = $\infty$) to lower state (n = 3) has occurred. Energy has been emitted in this case.